Martin Rundkvist's blog for 2006. Archaeology, skepticism, Sweden. And books and music and stuff.Continued at Aardvarchaeology.

Friday, June 30, 2006

Build Yourself a Brain

This is really way cool. Biologist blogger PZ Myers summarises brand new research into the neurology of the octopus's brain. Octopi are smart and have good memory thanks to their large and intricate brains. This biocomputer is in some senses wildly different from our own: for instance, the gullet passes through the octopus's brain. This is hardly surprising as vertebrates and octopi are on very far branches of the bush of life: our last common ancestor didn't have any brain at all. We've evolved brains independently, just as we've got unrelated eye structures. Yet there are similarities too in the neuronal architecture, which suggests convergent evolution.

Convergent evolution is when organisms without any close relationship to each other evolve similar form under similar selection pressures. The most commonly quoted example is the similarities between swimming dinosaurs, dolphins and large fish such as sharks. They look pretty much the same, because that's the optimal way to build a successful marine predator. The similarities between the brains of vertebrates and octopi suggest that there are also optimal ways of wiring a biocomputer to build a smart animal.

The reason that I'm worked up about this is the implications it has for intelligent extraterrestrial life. Vertebrates and octopi have evolved similar thinking boxes independently starting from the humble neural heritage of mindless worm ancestors. It happened at least twice on Earth -- so it probably happens a lot on similar planets elsewhere!